This invention relates to spray apparatus and more particularly to automated apparatus for roadside spraying of herbicides which is mounted on a front of a vehicle and controlled by a operator of the vehicle.
Many state highway departments, counties and cities, have for several years been actively mowing and brush cutting undesirable weeds, grass and brush in their right-of-ways. This has been primarily accomplished by hand labor or mechanical means. Many of these publicly funded organizations have attempted to spray their right-of-ways with selective herbicides that would control the undesirable plant growth and leave predominantly low growing grasses. Two programs that have been used for several years are MSMA to control johnson grass and 2-4-D to control broad leaves and brush.
The equipment which has been used in the past has been of generally three types. A common type of equipment is the long boom extending out to the side of the truck and across the right-of-way. An example fo a long boom is shown in U.S. Pat. No. 2,995,307 issued to J. J. McMahon. The use of the handgun is still common today for lack of anything with more versatility. Another has been the use of an off-center nozzle mounted to the side of the truck. The use of the off-center nozzle is discussed further below.
The long-extending boom has been used widely because of its ability to reach 25 to 30 feet into the right-of-way. Some designs have provided the boom in sections to give the operator more flexibility as to where he could spray the herbicide. This has also allowed the operator to save chemical. A problem with this type of unit is that it does not lend itself to many right-of-way applications because of hills, back slopes and obstructions in the areas to be sprayed. Obstructions are believed to be a major problem. The extended boom is vulnerable to contact with obstructions causing extensive down time and delays with loss of production. It is also believed to be very expensive to replace such booms. The use of hydraulic cylinders mounted along the boom may make the application even more cumbersome since the driver may have to slow the speed of the spray truck upon the encountering of several obstructions, such as trees, signs, bluffs, and the like. Under such circumstances, the operator might get too little, or no herbicide at all in certain areas because the boom was raised to go over the sign and wind blew many of the small particles away or the sprayed area received excessive rates of the herbicide due to the slower speeds of the truck. In some situations it is necessary to use two operators. This increases the costs due to the extra labor required and often the spray may not get to the target area while passing over obstructions. Also long booms require the vehicle to have greater gross vehicle weight because a long spray boom attached to the front of the vehicle may require heavier axles and generally heavier duty vehicles to support the long beams.
It is believed that the off-center nozzle in many cases had advantages over the long booms because the operator could spray all day without worrying about obstructions in the right-of-way. This nozzle could be mounted anywhere to the side of the vehicle and the spray pattern covered an area beginning immediately beside the truck and extending from 10 to 30 feet out into the right-of-way. Wind velocity tended to dramatically effect the distance and in such circumstances the spray might not extend past 10 to 15 feet from the vehicle. This type of nozzle also did not give the operator much versatility to place a herbicide only in areas where undesired vegetation existed across the right-of-way. In practice, the weeds are often in spotted areas lying 20 to 40 feet away from the spray truck and the operator has no way to get the herbicide to the target, especially if the wind velocity over powers the spray. The operator also, in certain situations, needs to spray the herbicide next to the vehicle, where only undesirable taller growing vegetation exists. In certain situations this may cause more herbicide to be used than necessary such as with off-center nozzles, which unnecessarily may increase the costs of the spraying program.
The same problems also exist with controlling undesirable brush. A long extending boom as far as known, is not often used for this purpose. Generally the use of a handgun and the off-center spraying means are used in such situations. Spotted applications to the soil under the undesirable brush with the use of a handgun, spraying specially selected herbicides, provide easy control of brush. In such situations, herbicides were often used, whereby rain would carry the chemical into the root zone to be picked up by the brush. This type of chemical interfers in the natural processes in the plant causing its ultimate death. A problem with spotted application of such herbicides by handguns on such undesirable brush, is that it is slow, which increases application cost and in most cases the herbicide is overapplied resulting in excessively killing of low growing desirable ground cover.
With the development of new herbicides, especially new selective herbicides, it has become more important to eliminate the problem encountered with extended booms, off-center nozzles and handguns. In the case of certain chemicals, it is necessary to apply them from 1 to 11/2 quarts per acre or 43,560 square feet. In the case of other currently used chemicals, it is necessary to apply them at 4 to 8 ounces to control more susceptable tall growing vegetation. Greater amounts of these herbicides may kill the low growing, more tolerant species of vegetation and leave partial to total bare ground. Such problems often prevent many highway departments, counties and cities from going into vegetation management programs with the new herbicides to eliminate the more costly program of hand labor and mechanical mowing.
Applicant's invention helps overcome the above discussed problems. An object of the invention is to provide a spraying apparatus capable of spraying smaller particles in spray swaths adjacent to the vehicle and larger particles in areas farther away from the vehicle. An object of the invention is to allow an operator to spray the larger particles up to 40 feet away from the vehicle. Another object of the invention is to provide a spray pattern which is less affected by wind. Another object of the invention is to allow an operator to spray spotted weed problems at any location up to 40 feet away from the vehicle without wasting herbicide where only desirable low growing vegetation exists. Another object of the invention is to allow an operator the option of applying herbicides at exacting rates at selected locations across the right-of-way to prevent overuse of herbicide and potential damage to low growing grass, where no undesirable weeds exist. Another object of the invention is to provide a spraying apparatus which provides foliar applications of herbicides on brush at any selected location in the right-of-way. Other objects of the invention will be apparent from the following detailed disclosure.